<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">{{ message }}</div>
</body>
<script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
<script src="https://unpkg.com/vue-router@4.0.15/dist/vue-router.global.js"></script>
<script>
    const { createApp, ref } = Vue
  
    createApp({
      setup() {
        const message = ref('Hello vue!')
        return {
          message
        }
      }
    }).mount('#app')
  </script>  
</html>